Heat exchanger



Mam: 31. I925. I,531,400'

- B. M. JOHNSON HEAT EXCHANGER Filed Feb. 21 1924 3 Sheets-Sheet l March 31, 1925.

. B. M." JOHNSON Filed Feb. 21- 1924 5 Sheets-Sweet 2 ma 4. W

, EEl 6 lllll March 31*. 1925. 1,531,400

B. M. JOHNSON HEAT EXCHANGER Filed Feb. 21- 1924 3 Sheets-Sheet 5 INVENTOR Patented Mar. 31, 1925..

UNITED STATES, PATENT OFFICE,

BOYD M. JOHNSON, F ME'I'UCHEN, NEW

JERSEY, ASSIGNOR TO THE CARBORUNDUM (XDMPANY, OF NIAGARA FALLS, NEW YORK, A QQRPORATION OF PENNSYLVANIA.

Imam EXCHANGER Application filed Pepi-nary To all whom it may concern:

Be it known that I, BOYD M. Jom son, a citizen of the United States, residing at Metuchen, county of Middlesex, State of New Jersey, have invented a' new and useful Improvement in Heat Exchangers, of which the following is a full, clear, and exact description;

This invention relates broadly toheat eit- 0 changers, and more particularly to heat extype adapted for transferwaste gases to air or' ,other ly referredto as recuperachangers of the ring heat from gases, and genera tors. v

The-construction of refractory recuperators has been limited, due tothe difliculty of manufacturing the complicated shapes heretofore used in their construction. The present invention provides an eflicicnt reractory recuperator the main heat transfer portion of which is composed of simple thinwalled hollow tile placed open end to open end to form continuous flues for the passage of the Waste gases and spacer blocks completely encircling and sealing the joints between the hollow tile and forming with said tile a portion of the walls of a passage for the air entirely around the tile, said passage consisting of a plurality of individual flues. e invention is not limited to the use. of any particular, refractory material but I prefer toconstruct the tile and spacer blocks of silicon, carbide, because this material has certain properties which function together in a way to give most efficient results when employed as a heat transfer medium. These properties of silicon carbide areits high heat-emissivity factor, its high thermal conductivity, its low coetficient of expansion and its great mechanical strength, the latter property particularly enabling it to be employed in relatively thin sections without danger of rupture.

Certain preferred eu'ibodiineuts of my invention are shown in the accompanying drawings, in whic Figure 1 is a section through one form of recuperator, the section being taken on the line II of Figure 2;

Figure 2 is a section of the recuperator at right angles to the section of Figure 1, the section being taken on theline IIII of Figure l;

'the recupcrator through (V blocks surrounding the hollow tile form a plurality of independent right angles to the the lower bank of gas flues 21, 1954. Serial No. 694,262.

Figure 3 is a sectional plan View of the recuperator, the section being taken on the line IIIIII of Figure 2;

Figure 4 is a detail view on scale illustrating thc'mann'er of assembling the tile and spacer blocks;

Figure 5 is a sectional plan .view of another form of recupcrator, the section being taken on the line VV of Figure 6;

Figure 6 is a section of the recuperator shown in Figure 5, the section being taken on the line VIVI of Figure 7; and

Figure 7 isa section at right angles to the section of Figure 6, the section being taken on theline VII VII of Figure 6.

Referring to the form of invention shown in Figures 1 to 3, inclusive, the rccuperator comprises outer surrounding walls 2, a floor 3 and a roof 4, all of which are constructed of the usual fireclay refractory material. The waste gases enter the recuperator through an inlet 5, and after passing through a series of cont flues are constructed of tile; placed open cud to open end. dividual flues for the air The inare formed by plac- 1mg spacer blocks 8 between the fines 6, these spacer blocks being placed at and completely encircling the joints between-the hollow tile, thereby sealing thescjoints and preventing leakage of; air into the flues 6. The hollow tile-forming the flues 6 are preferably rectangular in cross section and preferably all of the same length, so that the spacer joints between the air flues 9 extending at gas flues 6. I

Vertical air intake flues 10 are formed in an outer fireclay wall 11, these vertical flues communicating with horizontal flues 12 in the base of the recupcrator. The horizontal'flues 12 are separated from each other by partition walls 13 which support 6, and cooperate with spacer blocks 8 to seal the joints be tween the hollow tile forming this lower bank of gas flues. The air cntering'a flue 10 passes to the horizontal flue 12' communicating therewith and then passes upwardly in a sinuous path through an air flue 9 and enters a space 14 between the inuous flues 6, leave an outlet 7. These thin walled hollow Y an enlarged lOO the side walls 17.

the .rccuperator.

placing the horizontal spacer they span spacer blocks placed above solid walls 17 extendingthe the tile and spacer the spacer blocks.

its

upper bank ot gas does (3 and the root of The heated air leaves this space through an opening 15 in saidroot and enters an otl' ake flue. 1(3. The gas tlues in cach'bank are staggered with relation to the gas Hues in the bank immediately below or above the some, thereby 'ausi ngdhe air in its upward flow through the air tlues 9 to wipe the four sides of the hollow tile tornungthc flues throughwhich the hot gases are passing" and also increasing the length of the path ottravel of the air.

The spacer blocks, being stronger than the hollow tile, are made to carry the major portion of the weight of the recuperator by blocks so that the distance between thevertical spacer blocks. The vertical spacer blocks thus transtcr the load imposed on the horizontal the tile to the horizontal spacer blocks placed beneath the tile. In this way much of the strain is taken 't'rom the thin-walled hollow tilc forming the gas tlucsi The manner in which thohollow tile and the spacer blocks are assembled will be more apparent by reter once to Figure 4.

The outer portions of the recuperator which allow for either ingress or egress of Waste gases or air must naturally beopen, but along the sides of the heat transfer portion of the rccuperator which do notallow for passage of waste gases or air are 'ilaced entire height and length of the heat transfer portion of the recupcrator. These Walls together with block form the walls of the air flues Sand are spaced trom theouter fireclay Walls 2 of the recupcrator in order to allow expansion joints between the walls 17 and the outer walls 2. Battles 18 con-. trol the flow' of the waste gases through the recuperator and these battles extend between the ends of certain of the gas tiues '6 and take the place f spacer blocks 8. At their outer ends these battles are supported upon walls 19 and 20 integral with The tile forming the gas fiues, the spacer blocks. the baffles 18 and the walls '13, 17,19 and 20 are all formed of the saline refractory material, so that there will be no differences in expansion and consequentleslaage due to displacement of All of the hollow tile will preferably he made in which case the battles v I i 17, 119 and 20 willalso be construot'ed'of silicon carbide. The solid. Walls 17 ofsilicon carbide forming the side walls of the heat transfer portion oi the and spacer blocks of silicon. carbide, 18 and walls 13,

"recuperator and a ortion otthe walls of the sin assage whi e they prevent leakage dueto isplaceme'nt under unequal expans1on, also perm t for the allowance or a sutl'lcient expansion ouit between the main rsoo oint rehody of ing lireclay walls, such exp-ah. lieviug the recuperator of an .to a decrease in the width of t; ing chamber formed bythez walls 2. V

it will be noted .urroiind iirecley by reference to Figu. es 1 and 2 that the uppermost courses of horizontal spacer blocks are bridge-cl at the joints by transxersely extending: slabs 21. These slabs will be constructed ot the same refractory material as the tile and other parts of the heat transfer p ortiono't' the recuperator. 'lhese slabs are siihply utilized as additional heat transfer elements and to further increase the length oi the path of travel otthe air; it will. further be noted that in orer to oil's ct the gas dues in one bank from those in the bank below or above the same, 3 employ tor certam ot the tines tile having'one halithe width oi the tile forming: the other tlues.

in Figures 5, 6 and I l have illustrated a forrnlot' recupcrator-particularly adapted for use where the vertical space available for the recuperator is limited. lo this form of the invention the waste gases enter the recuperator through ass throu h a series ot gas lines 2?; formed of hollow tile in the same manner as the 1 gas Hues 5. Battles compel h to make several pa'zsses the wie rec-operator hot-ore leaving; the recrouerator through the outlet 25. 'lheaizf recuperator through aseries ot vertical fines 26 separated ii-om each othcrlw pa'rtitiou wallsQZ. These llues communicate with horizontal air tlucs 9.8 formed by the spacer blocks 29 which. surround the tile otthe 5 lines at the joints between such tile. At t passing through t Q I The tile forming the three F ll/yids :pacer blocks 25), and-baffles e posts 353 and the walls 36 will all so ied of the same refractory material, oreiterahy SllflCOIl carhide, so that there will he no dillerence iii" expansion and consequent leakage due the displacement of the spacer blocks surround ing thcijoints between the tile.

From the above description the advantages of my invention will be apparent to immediately 7 inlet andltli and scraper blocks.

those skilled in the art. The main heat transfer portion of the reciiperator is constructed of'simple thin-nalled hollow tile v The tile are formed without-tongues. or grooves. laps or other complicated joints. and the spacer "blocks which adequately seal the joints between the tile are plain rectangular shapes, easily manufactured. hollow tile the same length and placing them in banks so that the end joints are' in vertical planes, the spacer blocks form vertical solid division walls, thus dividing the space between the gas fines into a series of fines for the air instead of one continuous passage. This is a decided advantage since, should a hollow tile crack or break, the efficiency of the recuperator would only be decreased by leakageof air from a single air flue rather than from the entire space allowed for air travel. These division walls are carried to the inlet for the air. so that any air fiuemay be shut off entirely if desired and the remainingportions of the recnperator operated. This enables a run to be completed without materially reducing the efliciency of the recuperator. The sinuous flow of the air allows the maximum of contact with the surfaces transmitting the heat. and by such sinuous flow prevents any stratification of the air in its travel, as each ascending column of air impinges directly on a heated surface; By this method of con struction, the entire heat exchange portion of the recuperator is free and self supporting, and since such portion is constructed of the .same material, each integral part of such portion will hold its original relation to every other part threof'with changes in temperature. The construction is such, moreover,'that sufiicicnt space is allowed at the ends of the gas fines for ready inspection between runs and for minor repairs. By the construction employed, the weight of the heat exchange portion of the recuperator is carried largely by the spacer blocks, thus relieving the weaker hollow tile from excessive strains and permitting tile having very thin walls to be employed.

While the general construction is applicable to any refractory material of reasonably high heat conductivity, the construe,- tion is particularly applicable to silicon carbide because'its high refractorin'ess and low co-efiicient of expansion insure long life and its high heat conductivity and emissivity render this material the most efiicient refractory heat transmitting 1 dium. Due to the fact that silicon carbide has a high heat conductivity, the spacer'bloolrs as well as the-hollow tile walls will readily take heat lrom thosc portions of the hollow tile covered by the spacer blocksand will in turn give up such heatto the air. The use of these solid spacer. blocks will, therefore,

By constructing all of the not materially reduce the effective heat trans mittingsu'rface of the hollow tile.

While I have shown and described certain preferred embodiments of my invention, it will be understood that changes may he made in the details of construction shown without departing from the spirit of the invention or scope of my broader claims.

I claim:

1. A heat exchanger, comprising gas fluos formed of hollow tile placed open end to open end, and spacer blocks scal ng the jointsdiictween the tile of said fines and forining with said tile :1 portion of the walls of it passage for the medium to be heated,

substantially as described.

2. A heat exchanger, comprising gas fines formed of hollow tile of the same length placed open end to open end and having all corresponding end joints located in the same plane, and spacer blocks scalin said joints and forming with said tile a portion of the Walls of a series of individual lines for the passage of the medium to be heated, substantially as described.

3. A heat exchanger, comprising a plurality of banksof'gas iiues formed of hollow tile placed open end to open end, the flues in spect to the fines inthe bank on either side thereof, and spacer blocks sealing the joints between the tile of said flues and forming with said tile a portion of the walls of a passage for the medium to be heated, substantially as described.

' 4. A heat exchanger, comprising gas fiues formed ofhollow tile plac, d open end to open end, and vertical and l f'jzontal spacer blocks sealing the joints between the tile of said'flues and formingwith szlid tile 21. portion of the walls of a passage tor the medium to be heated, said spacer blocks being arranged so that the horizontal blocks span the. distance between the verticatl blocks and are supported by the latter, substantially as described.

5-.- A heat exchanger, comprising gas fines formed of hollow tile of the same length placed open. end to corresponding, end joints located in the same vertical plane, and vertical and horizontal spacer blocks sealing said joints and forming with said tile 2. portion 0 rice of individual fines for the passage of the medium to be heated, said spacer blocks. being arranged so that the horizontal blocks span the distance between the vertical blocks and are supported by the latter, substantially described.

6. A heat exchanger, comprising outer.

lls defining a chamber, a pluralit of gas ii es within said chamber formed 0? hollow tile placed open end to open end, spacer blocks sealing the joints between the tile of said fines an forming with said tile a per open endand having all I one bank being staggered with rc- 5 the walls of a setion of the walls of a passage For the medium to be heated, hatlle plates extending between the ends of certain of the, lines, and lining walls supporting the outer ends of said ballle plates and spac d from the ends of the gas lines, the tile, spacer blocks, ballle plates and lining walls being l'ormed oi the same refractory material. substantially as described.

T. A heat exchanger," comprising outer walls defining a chamber, a.1.luralitv of gas lines within said chamber l'ormed oi hollow til piaced open end to open end; spacer blocks sea ing the joints between the tile of said lines and forming with said tile a portion of the walls of a plurality of individual fines for the passage of the medium to he heated. and an individual inlet line for each of said last mentioned tines, substai'itially as described.

S A heat exchai'iger, comprising outer walls defining a chan'iher. a plurality of gas lines within said chamber formed of hollow tile placed open end to open end, spacer blocks sealing the joints between the tile of said fines, and lining walls placed along the sides of the heat transfer portion of the heat exchanger formed by said lines and spacer blocks and torminp' with said tile and spacer blocks the walls ot a passage for the medium to be heated, said lining walls being spaced from the opposite outer side walls of said chamber to allow expansion between said lining walls and outer side walls, said tile,

spacer blocks and lining walls being; formed of the same refractory material. substantially as described.

9. A heat exchanger, comprising outer walls defining a chamber, a plurality of gas -with said tile'and fines within said chamber and having their opposite. ends spaced from'the opposite end walls of said chamber, said fiues being formed of hollow tile pla'ced open end to open end, spacer blocks sealing the joints between-the tile of said fines, lining walls placed alone the sides of the heat transfer portion of the heat exchanger formed by said fines and spacer blocks and forming spacer blocks the walls of a passage for the medium to be heated, said lining: walls being! spaced from the opposite outer side walls oi' said chamber to allow expansion between said lining walls and outer side walls, and lining;- walls for the outer end walls of said chamber, said tile, spacer vblocks and lining walls being formed of the 'same refracti'n'y material, substantially as described.

10. A heat exchanger, comprising outer walls defining a chamber, and heat trailsl'er means within said chamber comprising a plurality of gas fines formed of hollow tile )laced open end to open end, spacer blocks sealing: the joints between the tile of i said fines and forming with said fines a portion of the walls of a passage for the medium to be heated, and walls supporting said heat transfer means in spaced relation to the floor of said chamber, the spaces between said supporting walls forming fines for conductingthe medium to be heated to said passage, the' tile spacer blocks and supporting walls being formed of the same refractory material, substantially as described.

In t stimony whereof I have hereunto set my d,

' BOYD M. JOHNSON 

